FRCR 1 ANATOMY QUESTION : 6

Sagittal T1 Weighted MRI Brain

Name the labelled structure ?

FRCR 1 ANATOMY QUESTION : 5

AXIAL CT Section - Skull Base

Question 5 : Name the labelled ?

FRCR 1 ANATOMY QUESTION : 4

Sagittal  T1 Weighted MRI

FRCR Anatomy Practice Question 4 : Name the structure labelled ?

FRCR 1 ANATOMY QUESTION : 3

Sagittal T1 Weighted MRI Brain

Question 3 : Name the labelled structure ?

FRCR 1 ANATOMY QUESTION : 2

AXIAL post contrast CT

 

Q2 : Name the labelled Structure ?

Solitary Pulmonary Nodule : Probability being Malignant

Solitary Pulmonary Nodule : Probability being Malignant : in decreasing order (Ss)

Spiculated margins
Size >3cm (defnitionwise this would be a 'mass' !!)
Seventy or more (>70yrs)
Speedy growth rate (Rapid doubling time)
Smoker
Superior location (Upper Lobes)

FRCR 1 ANATOMY QUESTION : 1

Q1 : - Name one anatomical structure located in the marked location. Can you also spot the main finding of this X-Ray?

AIR CRESCENT SIGN

Causes of AIR CRESCENT SIGN

    1. Aspergilloma -(Most Common).
    2. Angioinvasive.A.
    3. Echinococcal cyst.
    4. TB.
    5. Rasmussen aneusrysm
    6. Lung abscess
    7. Bronchogenic Ca.
    8. Hematoma.
    9. PCP.

Saprophytic aspergillosis (Aspergilloma) is commonly associated with thickening of the wall of the cavity and adjacent pleura (due to hypersensitivity reaction). The pleural thickening may be the earliest 'radiographic' sign before any visible changes in the cavity.

The 5 forms of PULMONARY ASPERGILLOSIS include:

1. SAPROPHYTIC

2. Allergic Broncho Pulmonary Aspergillosis (ABPA) / Hypersensitivity reaction.
- Long standing bronchial   asthma;
- Finger-in-Glove appearance,
- Segmental and Subsegmental bronchi of upper lobes
- fungal hyphal impaction of affected bronchi with distal mucoid impaction with 30% showing hyperdensity /   frank calcification in CT.

3. SEMI-INVASIVE / Nectrotizing Aspergillosis.
4. AIRWAY INVASIVE.
5. ANGIOINVASIVE ASPERGILLOSIS.

Ref : RG article, 2001.

Age related changes of Spinal Bone Marrow in T1 MRI

·   Human beings are born with red / hematopoietic marrow in their entire skeleton, which gets gradually replaced by fat as age progresses, and reaches the mature state by the age of 25years.

·          

    In adult pattern the red marrow is seen in the axial skeleton and proximal appendicular skeleton.

·          

    The red / hematopoietic marrow SI in neonates may be slightly lower than that of the skeletal muscle; thereafter marrow the signal intensity increases. So if the Marrow SI is found to be lower than of the normal skeletal muscle it almost always indicate a marrow pathology.

·           

    Under 40yrs of age, the axial skeleton contains fat only at the basivertebral vein region.

·          

    The replacement of the red to yellow marrow can occur in 3 patterns :

1.      Bandlike pattern along the endplate.

2.      Small foci of replacement.

3.      Larger globular areas of fatty replacement.

·              

    Near complete fatty replacement may be seen in some elderly patients and in cases of malnutrition or osteoporosis.

·           

    Conditions increasing the need for hematopoiesis like Chronic hypoxia, Anemia etc can cause reversal of fatty replcament, back to red marrow. These are usually seen as patches of T1 hypointensity.

·          

In cases of Sickle cell disease where the yellow marrow,can convert back to red marrow OR may never convert Yellow.
     
    The red marrow contains 40% of fat and yellow marrow contains 80% of fat !!!


      Ref  : AJR article MRI of spinal bone marrow -Part I. 2011.

The Chiari I Malformation

The main finding in Chiari Type I malformation is the Cerebellar Tonsillar Descent, resulting in the synonym of Congenital Tonsillar Ectopia. The measurements of the Clival length, Supraocciput, the tentorial slope and the Tonsillar Descent have been depicted in these following images.

MEASUREMENT OF CLIVAL LENGTH

MEASUREMENT OF THE SLOPE OF TENTORIUM

MEASUREMENT OF THE SUPRAOCCIPUT

Associated Syringomyelia in the lower cervical and upper thoracic spinal cord.

MEASUREMENT OF THE TONSILLAR DESCENT from the McRae's Line

Renal Duplex Systems

  

Case of Bilateral Renal Duplex System

Patient is a 36year old female, with h/o right ureterocele excision. 

USG was done initially, in which there was a tubular anechoic structure in right adnexa, mimicking a Hydrosalpinx. TVS confirmed the structure to be a dilated lower ureter, which was showing peristalsis and was seen in continuity with the right VUJ. This type of Ureteric Dilatation (Possibly secondary to reflux) can be easily mistaken for a hydrosalpinx. See the link below.

 CASE REPORTS: 'Duplex Megaureter Misdiagnosed as a Hydrosalpinx on Ultrasound '

Since there was right upper calyceal dilatation, Right Duplex System was suspected. LK was normal at time of USG.

LK shows two ureters	LK shows two ureters

CT images showed bilateral entirely duplicated ureters, bilateral upper moeity hydronephrosis. Right superior moeity ureter was seen inserted at a lower than normal position, with abnormal segmental dilatation of the distal 8-9cm.

Fetal PCA

FETAL POSTERIOR CEREBRAL ARTERY (PCA)

• In this anomaly, the Posterior Communicating artery(PCom) is prominent, with hypoplastic / Absent P1. Original Fetal PCA has absent P1, which is very rare.   

• Unilateral right OR Unilateral left PCA has an incidence of ~10% each. Bilateral Fetal PCA has an incidence of ~8%.

• The calibre of the PCom can be same as or greater than the PCA, and thereby the blood supply to the occipital lobes will be derived from the ICA through the PCom. The importance of this comes when ICA gets occluded, and will involve the ACA, MCA and PCA territories altogether (which will be difficult to explain by embolization). 

• Fetal origin of the posterior cerebral artery occurs when the embryonic posterior cerebral artery fails to regress.

Following are Axial Sections of NECT Brain of a middle aged female, which shows possible bilateral fetal PCAs. Here the Basilar artery bifurcation is not visualized and bilateral PComs are seen prominent (fig.3).

Small Basilar Artery anterior to Pons	Prominent bilateral PComs
Prominent bilateral PComs
P2 starts here!	Further continuation of PCAs(P2)

Lumbosacral transitional vertebrae

SYNONYMS : Lumbosacral transitional segment, lumbarization, sacralization, lumbosacral transanomaly, borderline vertebra.

A lumbar segment with enlarged transverse elements and an upper sacral segment with  lumbar-type posterior elements are the two most common presentations.
The relationship of LSTV to back and leg pain has long been a subject of debate.
The association of back pain with antalgic scoliosis was first described by Bertolotti in 1917 
(sacralization douleureuse, Bertolotti’s syndrome).

Radiological Findings: 

LSTV is characterized by enlargement of the transverse process(es). Frontal and lateral views should be performed and preferably supplemented with an angulated view of the lumbosacral junction (Ferguson-Hibb view).

Note: L3 has the longest transverse process and L4 has a pointed TP. 

Castellvi et al described a radiographic classification system identifying 4 types of LSTVs on the basis of morphologic characteristics.

Type I includes unilateral (Ia) or bilateral (Ib) dysplastic transverse processes, measuring at least 19 mm in width (craniocaudad dimension).Here the transverse process is expanded toward its tip as a spatulated bony process that is < 19 mm with no obvious connection to the sacral ala. This anomaly has a dubious role in back pain syndromes.

Type II exhibits incomplete unilateral (IIa) or bilateral (IIb) lumbarization/sacralization with an enlarged transverse process that has a diarthrodial joint between itself and the sacrum. The joint is usually referred to as a pseudo-articulation and is marked radiologically by corticated opposing bony surfaces with a 1- to 2-mm joint space. The vertebral body is often small and wedged laterally with narrowing on the side of attempted union, often precipitating a scoliosis. On the lateral view, a transitional vertebral body will be wedged posteriorly and the inferior endplate length will typically be less than the superior endplate length by a ratio of 1.37 or less (squaring sign). The intervening disc and facet joints are usually hypoplastic.

Type III LSTV describes unilateral (IIIa) or bilateral (IIIb) lumbarization/sacralization with complete osseous fusion of the transverse process(es) to the sacrum, with no visible joint.

A : Ordinary AP View B: Cranially Angulated (tilt-up) X Ray with central beam parallel to L5-S1 Disc shows a right sided type III LSTV.

Type IV involves a unilateral type II (pseudo-joint type) transition with a type III (osseous fusion) on the contralateral side.


Ref : Lumbosacral Transitional Vertebrae @ AJNR
        ESR 3rd Edition.

Urinary Bladder Herniation

URINARY BLADDER HERNIATION

Herniation of the Urinary Bladder into the inguinal canal or femoral hernia was first describe by Plater in 1550.
Incidence of UB hernia in Inguinal hernia is ~ 1-3% (rare).

Has been divided into 3 types :

1. Paraperitoneal : Most frequent.UB remains extraperitoneal and remains medial to the peritoneal herniation.
2. Intraperitoneal : UB hernia is completely covered by the peritnoeal sac.
3. Extraperitoneal: UB alone herniates, with no peritoneal herniation.

Herniation of Bladder diverticulum is also described.

But the difference between Bladder Hernia and Diverticulum is that, bladder hernia contains all the components of Bladder wall.
Diverticulum is only an outpouching of the mucosa through the defect in muscular layer (Detrusor).

Cystocele is a midline projection of bladder, whereas Bladder Hernia is more lateral.

Bladder ears are a normal variant, most commonly seen in infants <6months.
However it's been seen in young children and adults.
It's also called as the 'Transitory Extraperitoneal Hernia of Bladder in Infants'.


These following CT Axial sections of an elderly male shows the herniation of UB into the right inguinal canal.

Hiatus Hernia

This elderly male patient had Hiatus Hernia, Duodenal Diverticulum and Urinary Bladder herniation !!! 

Duodenal Diverticulum - CT sections

Duodenal Diverticulum

Fenestrations and Duplications

A duplication is defined as two distinct arteries with separate origins and no distal arterial
convergence .

Fenestration, by contrast, is defined as a division of the arterial lumen into distinctly separate
channels, each with its own endothelial and muscularis layers, while the adventitia may be shared.